豬繁殖與呼吸綜合癥（porcine productive andrespiratory syndrome,PRRS）是由豬繁殖與呼吸綜合征病毒引起的以母豬繁殖障礙和仔豬呼吸哀竭為主要癥狀的傳染病,，該病近年來(lái)大面積發(fā)生于我國(guó)境內(nèi)，引起養(yǎng)豬業(yè)的巨大損失,。
中國(guó)科學(xué)院動(dòng)物研究所何宏軒研究組,，采用RT-PCR技術(shù)對(duì)2008年分離自河北石家莊地區(qū)的7株（LS-4, HM-1, HQ-5, HQ-6, GC-2, GCH-3和 ST-7）豬繁殖與呼吸綜合征病毒（PRRSV）進(jìn)行GP2, GP3, GP4, GP5 和 NSP2 基因的擴(kuò)增、克隆和測(cè)序,，與已知序列的毒株的相應(yīng)片段進(jìn)行同源性分析比較,，并對(duì)其分子特征進(jìn)行分析。結(jié)果表明：這7株病毒仍屬北美基因型,，同源性分析表明這些病毒株與北美洲原型代表株(VR-2332株)有80.8-92.9%的同源性,，與疫苗毒MLV有81.3-98.8%的同源性，與BJ-4株有80.7-92.9%同源性,。所有這七株變異病毒的NSP2蛋白都存在一個(gè)29個(gè)氨基酸序列的缺失,，賦予了這些病毒新的特征，而且這些氨基酸序列的缺失與病毒高致病性有關(guān),，與河北省其它的分離株雖屬于同一個(gè)大的分支,，但這些毒株的gp5蛋白存在廣泛的突變。
這一研究結(jié)果表明了目前豬的PRRSV病毒可能存在一種由傳統(tǒng)毒株向高致病性毒株演化的趨勢(shì),，并為將來(lái)野豬PRRSV的疫苗研究和免疫防控奠定了基礎(chǔ),。該工作得到國(guó)家科技部973、863和國(guó)家科技支撐項(xiàng)目支持,。(生物谷Bioon.net)
生物谷推薦原文出處：
BMC Microbiology doi:10.1186/1471-2180-10-146
Phylogenetic analysis and molecular characteristics of seven variant Chinese field isolates of PRRSV
Chengmin Wang1 , Bin Wu1,2 , Said Amer1,4 , Jing Luo1 , Hongmei Zhang3 , Yunhai Guo1 , Guoying Dong1 , Baohua Zhao2 and Hongxuan He1
1 National Research Center for Wildlife Born Diseases, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
2 College of Life Science, Hebei Normal University, Shijiazhuang, Hebei, 050060 China
3 Department of Life Science, Heze College, Heze, Shandong Province 274015 China
4 Department of Zoology, Faculty of Science, Kafr El-Sheikh 33516 Egypt
Background
Porcine reproductive and respiratory syndrome (PRRS) has now been widely recognized as an economically important disease. The objective of this study was to compare the molecular and biological characteristics of porcine reproductive and respiratory syndrome virus (PRRSV) field isolates in China to those of the modified live virus (MLV) PRRS vaccine and its parent strain (ATCC VR2332).
Results
Five genes (GP2, GP3, GP4, GP5 and NSP2) of seven isolates of PRRSV from China, designated LS-4, HM-1, HQ-5, HQ-6, GC-2, GCH-3 and ST-7/2008, were sequenced and analyzed. Phylogenetic analyses based on the nucleotide sequence of the ORF2-5 and NSP2 showed that the seven Chinese isolates belonged to the same genetic subgroup and were related to the North American PRRSV genotype. Comparative analysis with the relevant sequences of another Chinese isolate (BJ-4) and North American (VR2332 and MLV) viruses revealed that these isolates have 80.8-92.9% homology with VR-2332, and 81.3-98.8% identity with MLV and 80.7-92.9% with BJ-4. All Nsp2 nonstructural protein of these seven isolates exhibited variations (a 29 amino acids deletion) in comparison with other North American PRRSV isolates. Therefore, these isolates were novel strain with unique amino acid composition. However, they all share more than 97% identity with other highly pathogenic Chinese PRRSV strains. Additionally, there are extensive amino acid (aa) mutations in the GP5 protein and the Nsp2 protein when compared with the previous isolates.
Conclusions
These results might be useful to study the genetic diversity of PRRSV in China and to track the infection sources as well as for vaccines development.
